1. Field of the Invention
The present invention relates to a sensor for identifying the type of a magnetic recording medium (hereinafter referred to as a xe2x80x9cmediumxe2x80x9d) loaded on a tray, and, in particular, to a sensor for identifying a 128TR medium having a cut-out portion.
This application is based on Japanese Patent Application No. 11-69304, the contents of which are incorporated herein by reference.
2. Description of the Related Art
In a magnetic tape library using both a magnetic tape device for a 36-track medium (36TR medium) and a magnetic tape device for a 128-track medium (128TR medium), 36TR media and 128TR media are stored at the same time. Since the 36TR medium differs in the shape of the leader block from the 128TR medium, a tape extracting arm in the 36TR device cannot extract the leader block of the 128TR medium.
Generally, the medium is loaded into the library, and is mounted, and the tape is extracted. Based on whether or not the rotated extracting arm misses the leader block, the conventional technique identifies the type of the medium.
When the leader block of the 36TR medium is damaged, the extracting arm may miss the leader block, and the loaded 36TR medium may be mis-identified as a 128TR medium.
The magnetic tape library in general utilizes a robot hand for loading and unloading the medium. When a micro switch is used to identify the type of the medium, a movable switch portion 1a of the micro switch 1 is always raised as shown in FIGS. 8A and 8B, the movable switch portion 1a may interfere with the robot hand 2. In these figures, reference numeral 3 denotes the magnetic medium, and reference numeral 4 denotes a tray.
It is therefore an object of the present invention to provide a sensor for reliably identifying a 128TR magnetic medium based on the detection of a stronger section of the medium.
In order to accomplish the above object, the sensor for detecting a medium having a cut-out portion on a movable tray, according to the present invention, comprises: a rotatable first flag which is rotationally urged, the first flag, when contacting with the moved tray, being rotated in the anti-urging direction; a rotatable second flag which is rotationally urged in the reverse direction to the first flag, the rotation of the first flag being restricted by a stopper provided on the first flag; a flag detector which is turned on or off by the rotation of the second flag; and a cut-out portion detector for entering the cut-out portion of the medium.
According to the sensor of the present invention, when a medium having a cut-out portion is mounted in the magnetic tape device, the cut-out portion detector enters the cut-out portion of the medium, the second flag is rotated, and the flag detector is actuated.
When a medium without a cut-out portion is mounted on the magnetic tape device, the cut-out portion detector contacts with the medium and cannot be rotated, and the flag detector is not actuated.